Finding the hidden numbers

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Ganado (6784)

http://www.cplusplus.com/doc/tutorial/
http://www.cplusplus.com/doc/tutorial/basic_io/
http://www.cplusplus.com/doc/tutorial/control/
http://www.cplusplus.com/doc/tutorial/files/

What have you tried so far?

Note that if you have something like
std::ifstream fin("numbers.txt");

Each number can be extracted like:

int number;
fin >> number; // number will now contain the number from the file.

fin >> number; // number will now contain the second number from the file.
hint: loop

numbers and words

Note though that fin >> number; will fail and set fin into error state that has to be cleared before next input, if the next "word" is not a number.

A text that has some numbers somewhere is more challenging to read than a well formatted data, where you know when to expect numbers. (Although, well formatted data can still have errors.)

Ganado (6784)

Ah, missed that..

No, it's a list of word and numbers each on it own line..it's not a string

Be exact.
"word and numbers" as in "one word and many numbers" or "one word and one number"?

It's words and numbers

Like in
"cat dog badger 7 42"
or
"cat 7 dog 42 badger 9000"

Read the stream successively into a string until the stream dies.

For each string use string.find_first_not_of to determine whether it is all digits.

For any string that is purely digits, increment count if its length is less than 4.

It gets a tad more difficult if you allow negative numbers, floating point or any other acceptable representation of "number".

You may need to be more explicit about your requirements.

More like cat 7 dog 42 9000

#include <iostream>
#include <sstream>
#include <string>
using namespace std;

int main()
{
   stringstream in( "More like cat 7 dog 42 9000" );
   string word;
   int counter = 0;
   while ( in >> word )
   {
      if ( word.find_first_not_of( "0123456789" ) == string::npos && stoi( word ) < 1000 ) counter++;
   }
   cout << "There are " << counter << " numbers less than 1000\n";
}

There are 2 numbers less than 1000

Thanks so much bro

It gives an error which says "use of undeclared identifier 'stoi'

Also the program needs to take input from a user

Dee5 wrote:
It gives an error which says "use of undeclared identifier 'stoi'

Time to upgrade your compiler to at least C++11.

The following would have the same effect here, as long as none of your numbers start with 0.
if ( word.find_first_not_of( "0123456789" ) == string::npos && word.size() < 4 ) counter++;

Dee5 wrote:
Also the program needs to take input from a user

You can change the while loop to run off any sequence of words. Only you know how you wish to take the input from the user:
- whole line?
- multiple lines?
- sequence of words ended by a sentinel.

Over to you.

Multiple lines sir

Multiple lines...

Dee5 wrote:
Multiple lines...

How do you propose to signal the end of those "multiple lines"?